Global analysis of mannitol 2-dehydrogenase in lactobacillus reuteri crl 1101 during mannitol production through enzymatic, genetic and proteomic approaches

Several plants, fungi, algae, and certain bacteria produce mannitol, a polyol derived from fructose. Mannitol has multiple industrial applications in the food, pharmaceutical, and medical industries, being mainly used as a non-metabolizable sweetener in foods. Many heterofermentative lactic acid bacteria synthesize mannitol when an alternative electron acceptor such as fructose is present in the medium. In previous work, we reported the ability of Lactobacillus reuteri CRL 1101 to efficiently produce mannitol from sugarcane molasses as carbon source at constant pH of 5.0; the activity of the enzyme mannitol 2-dehydrogenase (MDH) responsible for the fructose conversion into mannitol being highest during the log cell growth phase. Here, a detailed assessment of the MDH activity and relative expression of the mdh gene during the growth of L. reuteri CRL 1101 in the presence of fructose is presented. It was observed that MDH was markedly induced by the presence of fructose. A direct correlation between the maximum MDH enzyme activity and a high level of mdh transcript expression during the log-phase of cells grown in a fructose-containing chemically defined medium was detected. Furthermore, two proteomic approaches (2DE and shotgun proteomics) applied in this study confirmed the inducible expression of MDH in L. reuteri. A global study of the effect of fructose on activity, mdh gene, and protein expressions of MDH in L. reuteri is thus for the first time presented. This work represents a deep insight into the polyol formation by a Lactobacillus strain with biotechnological potential in the nutraceutics and pharmaceutical areas.Fil: Ortiz, María Eugenia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; ArgentinaFil: Bleckwedel, Juliana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; ArgentinaFil: Fadda, Silvina G.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; ArgentinaFil: Picariello, Gianluca. Istituto Di Scienze Dell'alimentazione; ItaliaFil: Hebert, Elvira Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; ArgentinaFil: Raya, Raul Ricardo. University of Toronto; Canadá. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; ArgentinaFil: Mozzi, Fernanda Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; Argentin

Pasta fortified with C-glycosides-rich carob (Ceratonia siliqua L.) seed germ flour: Inhibitory activity against carbohydrate digesting enzymes

Carob (Ceratonia siliqua L.) seed germ flour (SGF) is a by-product resulting from the extractionextraction of locust bean gum (E410), which is a texturing and thickening ingredient used for food, pharmaceutical and cosmetic preparations. SGF is a protein-rich edible matrix and contains relatively high amounts of apigenin 6,8-C-di- and poly-glycosylated derivatives. In this work, we prepared durum wheat pasta containing 5 and 10 % (w/w) of SGF and carried out inhibition assays against type-2 diabetes relevant carbohydrate hydrolysing enzymes, namely porcine pancreatic α-amylase and α-glycosidases from jejunal brush border membranes. Nearly 70–80% of the SGF flavonoids were retained in the pasta after cooking in boiling water. Extracts from cooked pasta fortified with 5 or 10% SGF inhibited either α-amylase by 53% and 74% or α-glycosidases by 62 and 69%, respectively. The release of reducing sugars from starch was delayed in SGF-containing pasta compared to the full-wheat counterpart, as assessed by simulated oral-gastric-duodenal digestion. By effect of starch degradation, the SGF flavonoids were discharged in the water phase of the chyme, supporting a possible inhibitory activity against both duodenal α-amylase and small intestinal α-glycosidases in vivo. SGF is a promising functional ingredient obtained from an industrial by-product for producing cereal-based foods with reduced glycaemic index.Fil: Siano, Francesco. Consiglio Nazionale delle Ricerche; ItaliaFil: Mamone, Gianfranco. Consiglio Nazionale delle Ricerche; ItaliaFil: Vasca, Ermanno. Universita di Salerno; ItaliaFil: Puppo, Maria Cecilia. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos; ArgentinaFil: Picariello, Gianluca. Consiglio Nazionale delle Ricerche; Itali

A new hybrid bacteriocin, Ent35–MccV, displays antimicrobial activity against pathogenic Gram-positive and Gram-negative bacteria

Bacteriocins and microcins are ribosomally synthesized antimicrobial peptides that are usually active against phylogenetically related bacteria. Thus, bacteriocins are active against Gram-positive while microcins are active against Gram-negative bacteria. The narrow spectrum of action generally displayed by bacteriocins from lactic acid bacteria represents an important limitation for the application of these peptides as clinical drugs or as food biopreservatives. The present study describes the design and expression of a novel recombinant hybrid peptide combining enterocin CRL35 and microcin V named Ent35?MccV. The chimerical bacteriocin displayed antimicrobial activity against enterohemorrhagic Escherichia coli and Listeria monocytogenes clinical isolates, among other pathogenic bacteria. Therefore, Ent35?MccV may find important applications in food or pharmaceutical industries.Fil: Acuña, Leonardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucuman. Instituto Superior de Investigaciones Biologicas; ArgentinaFil: Picariello, Gianluca. Consiglio Nazionale delle Ricerche. Istituto di Scienze dell’Alimentazione; ArgentinaFil: Sesma, Fernando Juan Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; ArgentinaFil: Morero, Roberto Dionisio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucuman. Instituto Superior de Investigaciones Biologicas; ArgentinaFil: Bellomio, Augusto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucuman. Instituto Superior de Investigaciones Biologicas; Argentin

Differential Protein Expression in Berry Skin from Red Grapes with Varying Hybrid Character

Protein expression from the berry skin of four red grape biotypes with varying hybrid character was compared at a proteome-wide level to identify the metabolic pathways underlying divergent patterns of secondary metabolites. A bottom-up shotgun proteomics approach with label-free quantification and MaxQuant-assisted computational analysis was applied. Red grapes were from (i) purebred Vitis vinifera (Aglianico cv.); (ii) V. vinifera (local Sciascinoso cv.) grafted onto an American rootstock; (iii) interspecific hybrid (V. vinifera × V. labrusca, Isabel), and (iv) uncharacterized grape genotype with hybrid lineage, producing relatively abundant anthocyanidin 3,5-O-diglucosides. Proteomics supported the differences between hybrids and purebred V. vinifera grapes, consistently with distinct phenotypic metabolite assets. Methanol O-anthraniloyltransferase, which catalyses the synthesis of methyl anthranilate, primarily responsible for the "foxy" odour, was exclusive of the Isabel hybrid grape. Most of the proteins with different expression profiles converged into coordinated biosynthetic networks of primary metabolism, while many possible enzymes of secondary metabolism pathways, including 5-glucosyltransferases expected for hybrid grapes, remained unassigned due to incomplete protein annotation for the Vitis genus. Minor differences of protein expression distinguished V. vinifera scion grafted onto American rootstocks from purebred V. vinifera skin grapes, supporting a slight influence of the rootstock on the grape metabolism

Homology-based modeling of universal stress protein from listeria innocua up-regulated under acid stress conditions

An Universal Stress Protein (USP) expressed under acid stress condition by Listeria innocua ATCC 33090 was investigated. The USP was up-regulated not only in the stationary phase but also during the exponential growth phase. The three dimensional (3D) structure of USP was predicted using a combined proteomic and bioinformatics approach. Phylogenetic analysis showed that the USP from Listeria detected in our study was distant from the USPs of other bacteria (such as Pseudomonas spp., Escherichia coli, Salmonella spp.) and clustered in a separate and heterogeneous class including several USPs from Listeria spp. and Lactobacillus spp. An important information on the studied USP was obtained from the 3D-structure established through the homology modelling procedure. In detail, the Model_USP-691 suggested that the investigated USP had a homo-tetrameric quaternary structure. Each monomer presented an architecture analogous to the Rossmann-like α/β fold with 5 parallel β-strands and 4 α-helices. The analysis of monomer-monomer interfaces and quality of the structure alignments confirmed the model reliability. In fact, the structurally and sequentially conserved hydrophobic residues of the β-strand 5 (in particular the residues V146 and V148) were involved in the inter-chains contact. Moreover, the highly conserved residues I139 and H141 in the region α 4 were involved in the dimer association and functioned as hot spots into monomer-monomer interface assembly. The hypothetical assembly of dimers was also supported by the large interface area and by the negative value of solvation free energy gain upon interface interaction. Finally, the structurally conserved ATP-binding motif G-2X-G-9X-G(S/T-N) suggested for a putative role of ATP in stabilizing the tetrameric assembly of the USP. Therefore, the results obtained from a multiple approach, consisting in the application of kinetic, proteomic, phylogenetic and modelling analyses, suggest that Listeria USP could be considered a new type of ATP-binding USP involved in the response to acid stress condition during the exponential growth phase

Excretion of dietary cow’s milk derived peptides into breast milk

Nanoflow-HPLC-tandem mass spectrometry (MS/MS) was used to analyze the peptide fraction of breast milk samples collected from a single non-atopic donor on different days (ten samples) after receiving an oral load of cow’s milk (by drinking 200 mL of bovine milk). In addition, breast milk was sampled from the same lactating mother over a 6-h period at 5 time points after drinking cow’s milk. We aimed to trace the intra-individual variability and to define a time profile of the excretion of dietary peptides into breast milk. Overall, 21 peptides exclusively originating from both bovine caseins and whey proteins with no match within the human milk proteome were identified in the breast milk samples. These peptides were missing in the breast milk obtained from the mother after a prolonged milk- and dairy-free diet (three samples). The time course of cow’s milk-derived β-Lg f(125-135) and β-casein f(81-92) in breast milk

Correction: New knowledge on the antiglycoxidative mechanism of chlorogenic acid

Correction for 'New knowledge on the antiglycoxidative mechanism of chlorogenic acid' by Beatriz Fernandez-Gomez et al., Food Funct., 2015, DOI: 10.1039/c5fo00194c

computational fluid dynamics as a tool in the development process of left ventricular assist devices

Computational fluid dynamic analysis (CFD) have recently been applied in study the of cardiovascular system. Since the development of the first blood pumps in the early 1990's this mathematical technique has been adopted in determining pressure-flow relationship and efficiencies before building left ventricular (LV) assist devices (LVADs) prototypes. Improvements in the functionality of these devices are desirable and for this aim CFD could be a valid tool both in projection and development

Peanut digestome: Identification of digestion resistant IgE binding peptides

Stability to proteolytic degradation in the digestive tract is considered a general feature shared by most food allergens. Current digestibility models exclusively utilize purified allergen proteins, neglecting the relevant effects of matrix that occur for foodstuff systems. In the present study, we investigated digestion stability of the major peanut allergens directly in the natural matrix using an in vitro static model that simulates the gastrointestinal digestion including the oral, gastric, duodenal and intestinal (brush border membrane enzymes) phases. Immunogenicity was evaluated by Western Blot using N=8 pooled sera of peanut allergic pediatric subjects. Immunoreactive, large-sized and fragments of Ara h 2, Ara h 6 and Ara h 3 survived hydrolysis as assessed by SDS-PAGE. Smaller resistant peptides mainly arising from Ara h 3 and also Ara h 1 were detected and further identified by LC-high resolution-MS/MS. RP-HPLC purification followed by dot-blot analysis and MS/MS-based identification demonstrated that stable IgE-binding peptides derived from Ara h 3. These results provide a more realistic picture of the potentially allergenic determinants of peanuts that survived the human digestion, taking into account the role of the food matrix, which may significantly affect gastrointestinal breakdown of peanut allergens